Gradient coil with off center sweet spot for magnetic resonance imaging
US5278504A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1993 |
| Grant date | Jan 11, 1994 |
| Priority date | — |
| Expiry date | Mar 11, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/385
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An examination region (12) is defined along a z-axis offset from a geometric center (30) of a gradient coil assembly (20). Cylinders of a non-conductive, non-magnetic material support x, y, and z-gradient coils (24, 26, 22) for causing orthogonal magnetic field gradients through the offset examination region. The z-gradient coil (FIG. 2 ) includes a plurality of distributed loop arrays with a winding pattern selected to cause a region of linear magnetic field gradients in the z-direction in a region offset toward a cylinder first end (32). The x and y-gradient coils each include two pairs of oppositely disposed windings (FIG. 3 ) which include a pair of inner spirals (96, 98) offset towards the first end of the cylinder and an outer spiral (90) extending therearound. The outer spiral bows in (92) toward the cylinder first end and fans out (94) toward the second end. In this manner, the x, y, and z-gradient coils create linear magnetic field gradients along x, y, and z-directions which have a region of primary linearity offset from their geometric center.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.